HR: 10:35h
AN: H52B-02    [Abstracts]
TI: Low-dimensional modeling of hillslope subsurface flow: the relationship between rainfall, recharge, and unsaturated storage dynamics
AU: * Troch, P A
EM: patroch@hwr.arizona.edu
AF: Department of Hydrology and Water Resources The University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ 85721, United States
AU: Hilberts, A G
EM: arno.hilberts@wur.nl
AF: Hydrology and Quantitative Water Management Group Wageningen University, Nieuwe Kanaal 11, Wageningen, 6709 PA, Netherlands
AU: Paniconi, C
EM: Claudio_Paniconi@ete.inrs.ca
AF: Institut National de la Recherche Scientifique - Centre Eau, Terre et Environnement, Université du Québec, 490 de la Couronne, Quebec City, G1K9A9, Canada
AB: We present a coupling between the one-dimensional Richards equation for vertical unsaturated flow and the one- dimensional hillslope-storage Boussinesq equation (hsB, see [Troch et al., 2003]) for lateral saturated flow along complex hillslopes. Here, the capillary fringe is included in the flow domain as an integral part of the Boussinesq aquifer. The coupling allows quantatitive investigation of the role of unsaturated storage in the relationship between rainfall and recharge. The coupled model (hsB-coupled) is compared to the original hsB model (hsB- original) and a three-dimensional Richards equation (RE) based model (taken to be the benchmark) on a set of seven synthetic hillslopes, ranging from convergent to divergent. Using hsB-original the watertables are overestimated and the outflow rates are generally underestimated, and there is no delay between rainfall and recharge. The coupled model, however, shows a remarkably good match with the RE model in terms of outflow rates, and the delay between rainfall and recharge is captured well. We also see a clear improvement in the match to the water tables, even though the values are still overestimated for some hillslope shapes, in particular the convergent slopes. We show that, for the hillslope configurations and scenarios examined in this paper, it is possible to reproduce hydrographs and water table dynamics with a good degree of accuracy using a low- dimensional hydrological model.
DE: 1828 Groundwater hydraulics
DE: 1838 Infiltration
DE: 1850 Overland flow
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: 2007 Joint Assembly